This invention relates generally to apparatus for providing temperature control to a transportable body and more particularly, but not by way of limitation, to an air return bulkhead which can be removably installed inside a transportable body, such as a semitrailer or a truck body, adjoining a false ceiling removably mounted in the transportable body so that return air flowing through the false ceiling is returned directly to an air treatment mechanism through the bulkhead.
In the food industry many different types of food products, such as frozen foods and dairy products, generally diary products, packaged meats, and produce, as well as canned and packaged products, are frequently transported in a single trailer or truck body. When different types of products are carried in a single transportable body, each type is generally placed in its own compartment within the transportable body, which body is divided into compartments by movable or stationary insulated partitions. Because of the different types of products, a different temperature is often to be maintained in each compartment to insure that each type is properly preserved. Therefore, there is the general need for some type of apparatus which can be placed in a transportable body to provide different temperatures, as desired, in each compartment.
Several types of equipment have been used in the past to refrigerate or heat the air within a compartmented transportable body. However, these types have generally been built into the transportable body as an integral part thereof so that they cannot be removed without disassembling the body. Such integral types also cannot be added to old transportable bodies. Therefore, there is the more particular need for a temperature control apparatus which can be added to a transportable body either during its manufacture or after it has been manufactured.
Because many transportable bodies have mechanical refrigeration and heating systems for generally providing cooled or heated air within the body, there is the need for the temperature control apparatus to be compatible with such systems. In other words, the temperature control apparatus should be able to provide different temperatures for different compartments from a single source of mechanically refrigerated or heated air.
It is also desirable that the temperature control apparatus be constructed for more efficiently distributing refrigerated or heated air even when the transportable body is configured as a single compartment. The apparatus is also to be constructed with a relatively smooth surface so that more efficient sealing of a movable or removable partition can be effected within the transportable body when more than one compartment is defined therein.
Because the products which are to be transported in the transportable body are often stacked throughout the entire volume of the transportable body, the temperature control apparatus should also be constructed to prevent those products which come in contact with the apparatus from freezing when one compartment is to be maintained at a freezing or subfreezing temperature and an adjacent or other compartment is to be maintained at a temperature above freezing.
To insure accurate control of the temperatures in each compartment, the temperature control apparatus should also include temperature sensing means for sensing at least one temperature and appropriately controlling the apparatus to provide the proper amount of temperature-treated air to the respective compartments. This temperature-treated air is to be provided by a known type of mechanical refrigeration and heating unit, for example, and is to be recycled through the compartment into which the unit disperses the temperature-treated air. The temperature control apparatus should include suitable air channeling means for adequately receiving a selectable quantity of the temperature-treated air.
Furthermore, it is desirable that the temperature control apparatus be constructed to require a minimum amount of space so that the load space for cargo is not significantly reduced when the temperature control apparatus is installed in the transportable body.
The foregoing needs have been satisfied by my prior invention described in U.S. Pat. No. 4,531,377. In my prior invention, however, return air became mixed with air in the compartment adjacent the air treatment mechanism, which mixing could affect the temperature of the air within such compartment. Therefore, it has developed that there is the further need for an improved apparatus by which improved return air control is obtained to prevent mixing by directly conducting the return air into the intake of the air treatment mechanism.